The present invention relates to an electronic clinical thermometer and, more particularly, to an electronic clinical thermometer which selects one of prescribed predictive mathematical equations based on change of detected temperature in transition of temperature measurement time and displays a value obtained by calculating the selected equation as a measured body temperature. Also, the present invention relates to a method for verifying prediction precision of the electronic clinical thermometer.
Conventional prediction type electronic clinical thermometer obtains a predicted value using a prediction equation as follows: EQU Y=T+U
(Y: a predicted value; T: detected temperature; U: bias) PA1 (t=time elapsed from the prediction starting point)
The prediction starting point (a point in time where calculation of a predicted equilibrium temperature is started) corresponds to a point where a detected temperature becomes higher than a predetermined value and rate of temperature rise becomes higher than a predetermined value. Prediction validation point (a point in time where the prediction has been realized) corresponds to a point where variation of the predicted value stands within a predetermined range.
The bias U is obtained by various calculations: EQU U=a.sub.1 .times.dT/dt+b.sub.1 EQU U=(a.sub.2 .times.t+b.sub.2).times.dT+(c.sub.2 .times.t+d.sub.2)
Parameters a.sub.1, b.sub.1, a.sub.2, b.sub.2, c.sub.2 and d.sub.2 should be appropriate values in order to maintain precision of the bias U constant regardless of the patient or an element to be measured.
Further, temperature rise prediction data indicating temperature rise statuses are classified into several groups based on characteristics of the patients and elements to be measured, and sets of parameters corresponding to the groups are allotted to used equation. The bias U is weighted in order to maintain continuity of display values. If a weight function (M)=(t/50).sup.2 is used, the display value (H) is: EQU H=T+U.times.M
In this case, the value H displayed on a display unit becomes the predicted value Y at a point in time where the time t is 50 seconds.
The conventional electronic clinical thermometers have a disadvantage in that, once it starts prediction, it displays a predicted value even when the predictive mathematical equation or parameters are inappropriate. Also, when it judges that the equation or parameters are inappropriate, it does not display the value as an error. In such cases, if the prediction equation or parameters initially selected are inappropriate, or the predicted temperature and/or the detected temperature is unstable, the prediction precision is extremely lowered, or the prediction itself becomes impossible.
Further, in the prediction type electronic clinical thermometer which selects a prediction equations or parameters in accordance with a classified group of temperature rise data, the equation or parameters once assigned to groups are not changed. If the employed prediction equation or parameters are inappropriate, the prediction precision is degraded.
On the other hand, many samples by measurement are needed for evaluation of prediction precision (reliability) of the prediction type electronic clinical thermometer. Such measurement samples may include inappropriate data due to erroneous treatments by users, preventing exact verification. However, in the conventional thermometer, it is impossible to remove the inappropriate data, or if possible, whether or not to remove the data is decided by the user.